Conventionally, an ejector-type refrigeration cycle device having an ejector, provided with functions of a refrigerant decompression means and a refrigerant circulating means, is known. For example, Patent Documents 1-3 describe regarding an ejector-type refrigeration cycle devices, in which refrigerant discharged from a compressor is cooled by performing heat exchange with outside air in a radiator, and the cooled high-pressure refrigerant is decompressed in a nozzle portion of an ejector.
For example, in the ejector-type refrigerant cycle device of Patent Document 1, a gas-liquid separator is arranged at a downstream side of a diffuser portion of an ejector to separate low-pressure refrigerant into gas refrigerant and liquid refrigerant. Furthermore, a gas refrigerant outlet of the gas-liquid separator is connected to a refrigerant suction port of the compressor, a liquid refrigerant outlet of the gas-liquid separator is connected to a refrigerant inlet of a suction side evaporator, and a refrigerant outlet of the suction side evaporator is connected to a refrigerant suction port of the ejector.
Furthermore, in an ejector-type refrigeration cycle device of Patent Document 2, a branch portion is provided at an upstream side of a nozzle portion of an ejector to branch a flow of the refrigerant flowing out of a radiator. Furthermore, the branch portion is provided, such that one refrigerant branched at the branch portion flows toward the nozzle portion of the ejector, and the other refrigerant branched at the branch portion flows toward a refrigerant suction port of the ejector.
In addition, a discharge side evaporator is arranged at a downstream side of the diffuser portion of the ejector to evaporate the refrigerant flowing out of the diffuser portion of the ejector. A fixed throttle for decompressing and expanding the refrigerant and the suction side evaporator are arranged between the branch portion and the refrigerant suction port of the ejector so as to obtain cooling capacity in both the discharge side evaporator and the suction side evaporator.
In an ejector-type refrigeration cycle device of Patent Document 3, a branch portion is provided at a downstream side of a diffuser portion of an ejector to branch a flow of the refrigerant flowing out of the diffuser portion. Furthermore, the branch portion is provided, such that one refrigerant branched at the branch portion flows into the discharge side evaporator, and the other refrigerant branched at the branch portion flows toward a refrigerant suction port of the ejector via the suction side evaporator. Thereby, cooling capacity can be obtained in both the discharge side evaporator and the suction side evaporator.
In the ejector used for this-kind ejector-type refrigeration cycle device, high-pressure refrigerant is decompressed and expanded in the nozzle portion of the ejector to be jetted, and the refrigerant downstream of the suction side evaporator is drawn therein from the refrigerant suction port by a pressure decrease of the jet refrigerant, thereby recovering the loss of the kinetic energy in the decompression and expansion of the nozzle portion.
By converting the recovered kinetic energy (hereinafter, referred to as “recovery energy” to the pressure energy in the diffuser portion of the ejector, the pressure of the suction refrigerant of the compressor can be increased, thereby reducing the drive power of the compressor and improving the coefficiency of performance (COP) in the ejector-type refrigeration cycle device.